Jason Clarke Antiques has dated this piece to the 1880s.
Comprised of brass circular two part case and octagonal base for positioning on a binnacle type stand, with domed lid revealing a large seven and a half inch silvered compass dial or bearing plate on a double gimballed base.
The central column contains a large pointer, normally aligned to the course of the ship.

The company, A. Black & Co remains somewhat of a mystery but I have found one other example with very similar design characteristics made by D. McGregor & Co of Glasgow & Greenoch circa 1880.
The modern pelorus was invented in the 1850’s by Lieutenant Matthew Curling Friend of The Royal Navy (1792-1871) and Fellow of The Royal Society.
Jason Clarke Antiques has dated this piece to the 1880s.
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